Intravenous Immunoglobulin G Treatment Research Articles

Three or four doses of intravenous immunoglobulin G treatment for isoimmune hemolytic disease: A case series and literature review.

Neonates affected by isoimmune hemolytic disease (HDN) are at risk of developing severe hyperbilirubinemia. Studies show that increasing levels of bilirubin impact neonatal neurodevelopment. To avoid complications associated with exchange transfusion, intravenous immunoglobulin G (IVIG) is used to treat hyperbilirubinemia. We included all infants who received more than two doses of IVIG treatment for isoimmune hemolytic disease. We analyzed the incidence of side effects associated with IVIG treatment and the rate of exchange transfusion. A retrospective chart review performed between October 2011-October 2022 at East Carolina University Health identified neonates who received more than two doses IVIG for HDN. Neonates of postmenstrual age greater than 28 days old, receiving less than three doses of IVIG or received IVIG for other indications were excluded. The occurrences of adverse events, demographics and use of other medical therapies were reviewed. Eleven neonates were included in the case series. Most common cause of severe hyperbilirubinemia was attributed to ABO incompatibility. Six patients (54%) received three doses of IVIG, and five patients (45%) received four doses of IVIG with bilirubin levels decreasing below exchange transfusion. No treatment exceeding four doses of IVIG was reported, nor adverse events during treatment. In this cohort of neonates with HDN, bilirubin levels decreased after treatment with multiple doses of IVIG. Future research on recommendations of optimal total number doses of IVIG to reduce the risk for exchange transfusion.

Preemptive intravenous human immunoglobulin G suppresses BK polyomavirus replication and spread of infection in vitro

BK polyomavirus (BKPyV) infection causes various diseases in immunocompromised patients. Cells from human lung and kidney were infected with BKPyV and treated with commercially available intravenous immunoglobulin G (IVIG). Its effects on BKPyV replication and spread of infection were investigated, focusing on administration timing. IVIG treatment 3 hours after infection suppressed BKPyV replication assessed by real-time PCR and expression of the viral capsid protein 1 and large T-antigen. IVIG effectively reduced the number of BKPyV-infected cells 2 weeks after infection in an antibody titer-dependent manner. Virus release in the culture supernatants was not influenced by IVIG treatment 6-80 hours and 3-9 days after infection. Collectively, IVIG did not affect viral release from infected cells but inhibited the spread of infection by neutralizing the released virus and blocking the new infected cell formation, indicating greater efficacy in early localized infection. BKPyV replication resumed in IVIG-treated cultures at 7 days after IVIG removal. Early prophylactic administration of IVIG is expected to reduce the growth and spread of BKPyV infection, resulting in the reduction of infected cell lesions and prevention of BKPyV-associated diseases.

Outcomes of Empirical Treatment With Intravenous Immunoglobulin G Combined With Low-Dose Aspirin in Women With Unexplained Recurrent Pregnancy Loss.

BackgroundTo assess the clinical efficacy of intravenous immunoglobulin G (IVIG) administration combined with low-dose aspirin in women with unexplained recurrent pregnancy loss (RPL).MethodsWe retrospectively analyzed the medical records of patients who had been diagnosed with unexplained RPL and treated with IVIG and low-dose aspirin between January 2000 and March 2020 at Asan Medical Center. We analyzed pregnancy outcomes and their association with the percentage of natural killer (NK) cells.ResultsThe study analyzed a total of 93 patients and 113 natural and assisted reproductive technology pregnancy cycles. The live birth rate per cycle was 73.5% (83/113), and the term delivery rate was 86.7% (72/83). The live birth rate was high regardless of the type of RPL, method of pregnancy, timing of IVIG treatment, and presence or absence of autoantibodies. In addition, the live birth rate was significantly higher in patients who received IVIG more than once, compared with patients who received IVIG only once (77.8% vs. 42.9%, P = 0.006). There was no significant association between the NK cell counts and live birth rate (65.5% in the group with NK cell < 12%, and 69.7% in that with NK cell ≥ 12%, P = 0.725). Among all patients, 87.6% had no complications, and there were no congenital malformation among newborn babies.ConclusionIVIG combined with low-dose aspirin treatment showed favorable pregnancy outcomes regardless of the patient’s NK cell counts (%).

Maternal and fetal safety of intravenous immunoglobulin in women with reproductive failure.

Intravenous immunoglobulin G (IVIG) is an emerging regimen for women with reproductive failures (RF) during- or pre-pregnancy who have aberrant cellular immune reactions. Studies investigating teratogenicity of IVIG have been limited. Herein, we evaluated the fetal teratogenicity of IVIG and IVIG-related obstetric complications. Women who used IVIG during pregnancy due to RF with cellular immune aberrances were enrolled from four medical centers in Korea. The pregnancy outcomes were collected. A total of 370 RF women who used IVIG during their pregnancy were enrolled. Most of the patients started the IVIG therapy before 12weeks of gestation and 229 women continued IVIG treatment beyond 12weeks of gestation. The mean age of the subjects was 34.8 years and the mean total dosage of IVIG was 125.3g. A total of 307 women had livebirths and six of them were twins. Of 301 singleton livebirths, obstetric complications were developed as follows: preterm births (12.0%), gestational diabetes (7.0%), preeclampsia (4.0%), placental abruption (1.3%), placenta previa (4.3%), and placenta accrete (1.7%). Total six cases (1.99%) had major fetal anomalies in livebirths. The incidence of birth defects is similar to those of the general population in Korea and the previous report in infertile women. No IVIG -related viral contamination was noted. IVIG use during pregnancy did not increase obstetric complications and fetal teratogenicity. This study can be an evidence of maternal and fetal safety of IVIG administration during pregnancy.

A Systematic Review and Meta-regression Analysis on the Impact of Increasing IgG Trough Level on Infection Rates in Primary Immunodeficiency Patients on Intravenous IgG Therapy.

We conducted a systematic review and meta-regression analysis to evaluate the impact of increasing immunoglobulin G (IgG) trough levels on the clinical outcomes in patients with PID receiving intravenous immunoglobulin G (IVIG) treatment. Systematic search was conducted in PubMed and Cochrane. Other relevant articles were searched by reviewing the references of the reviewed article. All clinical trials with documented IgG trough levels and clinical outcome of interest in patients receiving IVIG treatment were eligible to be included in this review. Meta-regression analysis was conducted using Comprehensive Meta-analysis Software. Additional sensitivity analyses were undertaken to evaluate the robustness of the overall results. Twenty-eight clinical studies with 1218 patients reported from year 2001 to 2018 were included. The mean IVIG dose used ranges from 387 to 560mg/kg every 3 to 4 weekly, and mean IgG trough obtained ranges from 660 to 1280mg/dL. Random-effects meta-regression slope shows that IgG trough level increases significantly by 73mg/dL with every increase of 100mg/kg dose of IVIG (p < 0.05). Overall infection rates reduced significantly by 13% with every increment of 100mg/dL of IgG trough up to 960mg/dL (p < 0.05). This meta-analysis concludes that titrating the IgG trough levels up to 960mg/dL progressively reduces the rate of infections, and there is less additional benefit beyond that. Further studies to validate this result are required before it can be used in clinical practice.

Use of Intravenous Immunoglobulin G in HIT: Impact on Thrombosis and Mortality in a Population-Based Study

Introduction: Heparin-induced thrombocytopenia (HIT) is a severe prothrombotic syndrome with a mortality rate of 10% (Lancet Haematol. 2018 May; 5(5):e220-e231). Case reports show that Intravenous Immunoglobulin G (IVIg) can rapidly and durably counteract HIT antibody-mediated platelet activation in the setting of severe persistent HIT (Chest. 2017 Sep;152(3):478-485 and others). While this data supports use of IVIg in severe HIT, it is well documented that “positive result bias” enhances the likelihood of publication of studies that demonstrate salutary effects of interventions. IVIg has a black box warning for thrombosis which lists a number of potential predisposing states for this complication including hypercoagulable conditions (such as HIT). Thus, one concern is that of new/worsening thrombosis in HIT patients treated with this drug, something that is not evaluable with the limited publications in this area. The Nationwide Inpatient Sample (NIS) is the largest publicly available patient discharge database in the US that includes ~7 million discharges per year representative of discharges from all hospital types in the country. The goal of this study was to evaluate thrombosis, bleeding and mortality outcomes associated with IVIg use in HIT using the NIS database.Methods: Hospital discharges with an ICD-9-CM code for HIT (289.84) in the NIS were used to compare outcomes in adult patients (≥18yrs) who did and did not receive IVIg treatment (ICD-9-CM code 99.14) from October 1, 2008 to December 31, 2014. Discharges with diagnoses suggestive of a history of thrombosis (ICD-9-CM codes V12.51, V12.52, V12.55), idiopathic thrombocytopenic purpura (287.31), or secondary thrombocytopenia (287.4) were excluded. Patient characteristics included age, sex, all patient refined diagnosis related groups (APR-DRG) severity index, and APR-DRG mortality index. Outcomes included arterial thrombosis, venous thrombosis, bleeding, mortality, and a composite of all outcomes. Variables were compared by IVIg treatment status using survey weighted Chi-squared tests for categorical variables and ANOVA for continuous variables. Survey weighted multiple logistic regression was used to model each binary outcome by IVIg treatment status while adjusting for age, gender, APR-DRG severity index and mortality index. A matched analysis was performed as a sensitivity analysis for the multiple logistic regression results. Controls were matched with IVIg cases by exact gender, APRDRG severity index, and mortality index. Five matching controls were selected for each case based on nearest age. Conditional logistic regression was used to analyze each outcome using the matched dataset.Results: HIT patients treated with IVIg and those without were no different in age and sex (Table 1). Consistent with the limited published experience of IVIg use in HIT, those who received IVIg had more severe disease with greater likelihood of dying as indicated by their APR-DRG severity and mortality indices (Table 1). Multiple logistic regression showed that the adjusted odds ratio (aOR) was lower for all outcomes except bleeding in the IVIg-treated group, although this did not reach statistical significance (Fig 1; aOR of 0.766, 0.922, 1.049, 0.685 and 0.703 for arterial thrombosis, venous thrombosis, bleeding, death and composite outcome, respectively). Similar results were obtained in conditional logistic regression of matched data (Fig 2).Conclusions: Use of IVIg was not associated with worse thrombotic outcomes or mortality in HIT. On the contrary, results suggest a possible protective effect on these outcomes, but results did not achieve statistical significance possibly due to small numbers of IVIg-treated patients. The aOR was higher (but not significantly so) for bleeding in IVIg-treated HIT patients, however, this finding is consistent with the possibility that IVIg was used more frequently in patients who had more severe disease (and had already hemorrhaged), as suggested by worse APR-DRG severity and mortality indices in IVIg-treated patients. A prospective randomized treatment study may be necessary to provide conclusive data on IVIg efficacy and risk in HIT. [Display omitted] DisclosuresDhakal:Amgen: Honoraria; Celgene: Consultancy, Honoraria; Takeda: Honoraria. Aster:BloodCenter of Wisconsin: Patents & Royalties. Padmanabhan:Janssen Pharmaceuticals: Consultancy; GE Healthcare: Other: Material support for Clinical Quality Improvement Initiative; Retham Technologies LLC: Equity Ownership, Other: Retham seeks to develop HITDx(TM), a new assay for HIT diagnosis; BloodCenter of Wisconsin: Patents & Royalties: Patent/royalties for HIT diagnostic testing; Veralox Therapeutics: Other: Advisory Board; TerumoBCT: Consultancy.

Intravenous immunoglobulin G (IVIg) concurrently promotes Th2 and T regulatory cell development while abrogating Th17 cells

Abstract We aimed to further elucidate the mechanisms by which IVIg modulates the balance between Th17, Th2, and Treg. Using an OVA-driven murine model of allergic airway disease exhibiting a mixed Th17/Th2 response, we examined lung inflammation by H &amp; E staining and histology, and performed cellular phenotyping of lung homogenates using flow cytometry. In addition, we assessed cytokine production by intracellular staining and ELISA, and performed co-culture studies. IVIg treatment reduced lung inflammation and diminished the frequency and absolute number of lung Th17 cells, IL-17A production, and neutrophilia. In contrast, the frequency and absolute number of eosinophils and basophils was increased, while IgE production was abrogated in the IVIg group. This was accompanied by a significant increase in IL-13+ and IL-5+ T cells and in IL-5 concentration in the BAL. The frequency of Foxp3+IL10+ + cells within CD4+ T cells (1.43 % ± .061 vs 2.57 % ± .30, p &amp;lt; .01) and IL-10 secreting dendritic cells (0.28 % ± 0.060 vs 1.20 % ± 0.27, p &amp;lt; .05) was augmented. We also observed an increase in the frequency of CD206 expressing macrophages, or M2 macrophages, in the IVIg group (10.81% ± 2.21 vs 19.80 % ± 1.81, p &amp;lt; .01). Using an in vitro DC: T cell co-culture, IVIg-treated DC inhibited IL-17A production by T cells and increased IL-13 production and Treg differentiation. In conclusion, IVIg modulates Th2/Th17/Treg balance by favoring Treg and Th2 cells while inhibiting Th17 cells. Furthermore, IVIg renders both dendritic cells and macrophages tolerogenic.

Functional antibodies to Haemophilus influenzae type B, Neisseria meningitidis, and Streptococcus pneumoniae contained in intravenous immunoglobulin products

Intravenous immunoglobulin G (IVIG) replacement therapy is used to prevent invasive infections in patients with primary antibody deficiency (PAD). However, few studies have functionally evaluated specific antibodies against encapsulated bacteria that cause invasive infection in patients with PAD. In this study, functional antibodies against Haemophilus influenzae type b (Hib), Streptococcus pneumoniae (pneumococci), and Neisseria meningitidis (meningococci) in IVIG therapy were evaluated. Sixteen lots of IVIG products prepared by two Korean manufacturers (Products A and B) were evaluated. The functional antibodies were measured by serum bactericidal assay for Hib and four meningococcal serogroups and by multiplexed opsonophagocytic assay for 26 pneumococcal serotypes. The estimated trough levels of antibodies against Hib, pneumococcus, and meningococcus were calculated to determine whether the usual IVIG dose is appropriate for protecting patients with PAD. The functional antibody levels for Hib were similar in all of the IVIG products. In contrast, serum bacterial indices of meningococcal serogroups A and Y showed significant differences between products A and B. Opsonic indices to pneumococci varied depending on the serotype in each IVIG product. The estimated trough levels of antibodies against Hib, pneumococcus, and meningococcus exceeded the protective levels in most of the IVIG products except for the antibodies against two pneumococcal serotypes. Most of the tested commercial IVIG products had sufficient functional antibodies against Hib, pneumococcus, and meningococcus to protect patients with PAD receiving IVIG treatment. Regular and continuous evaluation of IVIG products is necessary to maintain an optimal therapeutic effect.

Deficiency in memory B cell compartment in a patient with infertility and recurrent pregnancy losses

Alterations in normal balance of B cell subsets have been reported in various rheumatic diseases. In this study, we report a woman with a history of recurrent pregnancy losses (RPL) and infertility who had low levels of memory B cells. A 35-year-old woman with a history of RPL and infertility was demonstrated to have increased peripheral blood CD19+ B cells with persistently low levels of memory B cell subsets. Prior to the frozen donor egg transfer cycle, prednisone and intravenous immunoglobulin G (IVIg) treatment was initiated and patient achieved dichorionic diamniotic twin pregnancies. During pregnancy, proportion (%) of switched memory B cells CD27+IgD− increased, while percent of total CD19+ B cells and CD27−IgD+ naive B cells were gradually decreased with a high dose IVIg treatment. She developed cervical incompetence at 20 weeks of gestation, received a Cesarean section at 32 weeks of gestation due to preterm labor, and delivered twin babies. B cell subset abnormalities may be associated with infertility, RPL and preterm labor, and further investigation is needed.

Exhaustion of bacteria-specific CD4 T cells and microbial translocation in common variable immunodeficiency disorders.

In the present study, we have investigated the functional profile of CD4 T cells from patients with common variable immunodeficiency (CVID), including production of cytokines and proliferation in response to bacteria and virus-derived antigens. We show that the functional impairment of CD4 T cells, including the reduced capacity to proliferate and to produce IFN-γ and IL-2, was restricted to bacteria-specific and not virus-specific CD4 T cells. High levels of endotoxins were found in the plasma of patients with CVID, suggesting that CD4 T cell dysfunction might be caused by bacterial translocation. Of note, endotoxemia was associated with significantly higher expression of programmed death 1 (PD-1) on CD4 T cells. The blockade of the PD-1-PD-L1/2 axis in vitro restored CD4 T cell proliferation capacity, thus indicating that PD-1 signaling negatively regulates CD4 T cell functions. Finally, we showed that intravenous immunoglobulin G (IVIG) treatment significantly reduced endotoxemia and the percentage of PD-1(+) CD4 T cells, and restored bacteria-specific CD4 T cell cytokine production and proliferation. In conclusion, the present study demonstrates that the CD4 T cell exhaustion and functional impairment observed in CVID patients is associated with bacterial translocation and that IVIG treatment resolves bacterial translocation and restores CD4 T cell functions.

Association of autoantibody specificity and response to intravenous immunoglobulin G therapy in immune thrombocytopenia: a multicenter cohort study

Immune thrombocytopenia (ITP) is a common autoimmune bleeding disorder, in which platelet glycoprotein (GP)IIb-IIIa and GPIb-IX are the two most frequently targeted autoantigens. Our previous studies in animal models of ITP demonstrated that intravenous immunoglobulinG (IVIG) could protect against anti-GPIIb-IIIa autoantibody-mediated thrombocytopenia but failed to ameliorate ITP induced by most anti-GPIb-IX autoantibodies. The objective of this human study was to evaluate the association between the specificity of antiplatelet autoantibodies and response to IVIG treatment. In this retrospective study, a cohort of 156 previously untreated adults with severe ITP who underwent IVIG therapy (0.4gkg(-1) day(-1) for 5days) was analyzed. The primary outcome was response defined as platelet counts of ≥30×10(9) L(-1) and a doubling of baseline counts within 7days of dosing, and an absence of bleeding. Among the 66 patients with anti-GPIb-IX autoantibodies, only 24 (36.4%) achieved a response, as compared with 72 of 90 patients (80.0%) who were negative for anti-GPIb-IX autoantibodies (relative risk 2.2; 95% confidence interval 1.6-3.1). This study found no difference in response between patients with anti-GPIIb-IIIa autoantibodies (61.7%) and those without anti-GPIIb-IIIa autoantibodies (61.3%). Logistic regressions, including main effects and the interaction between these two autoantibodies, showed no influence of anti-GPIIb-IIIa autoantibodies on the effects of anti-GPIb-IX autoantibodies with regard to their association with IVIG response. Thus, in adults with ITP, the presence of anti-GPIb-IX autoantibodies is a predictive factor for poor response to IVIG treatment. ClinicalTrials.gov NCT01666795.

Intravenous Immunoglobulin G Modulates Peripheral Blood Th17 and Foxp3+ Regulatory T Cells in Pregnant Women with Recurrent Pregnancy Loss

Th17 cells and Foxp3(+) regulatory T (Treg) cells have been proposed as new risk factors for recurrent pregnancy loss (RPL). Intravenous immunoglobulin G (IVIG) was reported to modulate various immune cells. In this study, we investigated the effect of IVIG on the levels of Th17 and Treg cells and pregnancy outcome in women with RPL. Thirty-seven pregnant women with RPL were enrolled in this study. All had cellular immune abnormality in preconceptional evaluation. Blood was drawn on the day of IVIG treatment and 1week later from the study subjects during early pregnancy. The proportions of IL-17(+) and Foxp3(+) T cells were analyzed using flow cytometry. Study population was divided into four groups (Q1-Q4) based on ascending order of the levels of Th17 and Foxp3(+) T cells. IVIG down-regulated Th17 cells in the highest quartile, Q4 (P=0.001), and up-regulated CD4(+) Foxp3(+) T cells in Q1 and Q2 (P=0.025 and 0.029, respectively). In addition, Th17/CD4(+) Foxp3(+) T cell ratio decreased in Q4 (P=0.040). We also found a positive trend between successful pregnancy outcome and CD8(+) IL-17(+) T cells before IVIG treatment (P=0.05). Intravenous immunoglobulin G treatment modulated imbalance of Th17 and Foxp3(+) Treg cells in pregnant RPL women with cellular immune abnormality.

Variability in Intravenous Immunoglobulin G Regimens for Autoimmune Neuromuscular Disorders

Aims: We reviewed the intravenous immunoglobulin G (IVIG) dispensing records of a specialty pharmacy to characterize the IVIG treatment regimens used for chronic inflammatory demyelinating polyneuropathy (CIDP) and myasthenia gravis (MG) in community practice. Methods: Anonymized records were selected based on International Classification of Diseases, Ninth Revision (ICD-9) codes and IVIG treatment for > 1 month. Each patient's immunoglobulin G (IgG) dose per infusion (mg/kg/dose) was multiplied by the number of doses per month (30.5 days divided by the dosing interval in days) to yield the total monthly dose (mg/kg/month). Data were analyzed and summarized using descriptive statistics. Results: Forty-six patients (median age, 56.5 years; range, 8−86 years) fulfilled the inclusion criteria. Thirty-one patients with CIDP received IgG at 7- to 92-day intervals (mean [standard deviation (SD)], 28 [16] days). The mean (SD) IgG dose was 75 (60) g/dose, equivalent to 866 (623) mg/kg/dose and 1145 (778) mg/kg/month. Six patients with stable MG received IVIG or subcutaneous IgG at 3.5- to 61-day intervals (28 [20] days) at a mean (SD) IgG dose of 39 (15) g/dose, equivalent to 405 (108) mg/kg/dose and 783 (680) mg/kg/month. Nine patients with MG with acute exacerbations received IgG at 7- to 42-day intervals (22 [12] days) at a mean (SD) dose of 40 (21) g/dose, equivalent to 403 (172) mg/kg/dose and 641 (288) mg/kg/month. One patient with CIDP and 4 patients with MG were treated with weekly subcutaneous IgG injections. Conclusion: Although patients with CIDP and MG are treated with mean total monthly IgG doses similar to those approved by the US Food and Drug Administration, the individual doses and intervals vary considerably, suggesting that physicians may be adjusting IgG dosing according to each patient's clinical condition and treatment response. Further study is necessary to determine the criteria used to adjust IgG treatment regimens and whether these adjustments optimize clinical outcomes while limiting overall costs.

Association between Platelet Autoantibody Specificity and Response to Intravenous Immunoglobulin G in the Treatment of Patients with Immune Thrombocytopenia.

Background: Recent studies in murine model of immune thrombocytopenia (ITP) suggest that autoantibodies against GPIba may cause thrombocytopenia through Fc-independent pathway and ITP mediated by anti-GPIb may be less responsive to intravenous immunoglobulin G (IVIG) treatment (Nieswandt B, et al. Blood 2000; Webster ML, et al. Blood 2006). The objective of this study was to investigate the potential association between platelet autoantibody specificity and response to intravenous immunoglobulin G (IVIG) treatment in patients with ITP.Methods: We retrospectively reviewed the clinical history of ITP patients who had platelet autoantibody test and received IVIG for treatment of thrombocytopenia. ITP was diagnosed by usual clinical criteria. All platelet autoantibody tests were performed by the Blood Center of Wisconsin (Milwaukee, WI) using ELISA, which detects antibodies reactive with platelet GPIIb/IIIa, GPIb/IX, and GPIa/IIa. A response was defined as a platelet count of > 50 x 109/L with a minimum increment of 30 x 109/L.Results: We found 17 patients who received IVIG and had platelet autoantibody test performed. The median age was 58 years (range, 20–83) and 10 (59%) were males. ITP was considered idiopathic in 12 patients. In the remaining 5 patients, the following hematologic conditions were present: chronic lymphocytic leukemia (2), Hodgkin lymphoma (1), myelodysplastic syndrome (1), and non-Hodgkin lymphoma (1). Antibodies reactive with GPIIb/IIIa, GPIb/IX, and GPIa/IIa were detected in 13, 10, and 8 patients, respectively. In 3 patients, none of these antibodies were detected. Among the 14 patients with antibodies, 9 (64%) had antibodies against more than 1 glycoprotein. The median pre-treatment platelet count was 9 x 109/L (range, 1–68). Overall, 10 (59%) patients responded to IVIG. A response occurred in 7 of 7 patients without anti-GPIb/IX but in only 3 of 10 patients with anti-GPIb/IX. The difference in the response rates between the 2 groups was statistically significant (P= .0098).Conclusions: Our clinical results support the murine model findings that ITP mediated by anti-GPIb may be less responsive to IVIG treatment. However, because of the small number of patients investigated and the retrospective nature of the study, our findings must be confirmed by other groups in a larger patient population.

Immune Thrombocytopenia Mediated by Anti-GPIbα Antibodies May Occur Via an FcR-Independent Pathway: A Potential Explanation for Refractory Cases to IVIG Therapy.

Intravenous immunoglobulin G (IVIG) is used to treat immune thrombocytopenia (ITP). While benefit has been observed in many cases, for unknown reasons some patients are refractory to this therapy. ITP is characterized by platelet clearance mainly mediated by antibodies against platelet surface glycoproteins (GP) GPIIbIIIa and GPIbα. Approximately 70–80% patients have antibodies against GPIIbIIIa, 20–40% patients have antibodies against GPIbα complex, and some patients have antibodies to both. Phagocytotic macrophages activated via their Fc receptors (FcR) are thought to be responsible for the clearance of opsonized platelets. However, anti-GPIbα antibodies may be able to induce ITP in an FcR-independent manner. Since the prevailing view of the mechanism of action of IVIG is Fc receptor blockade, we hypothesized that IVIG may not be effective at preventing thrombocytopenia induced by anti-GPIbα antibodies. Thrombocytopenia was induced in BALB/c mice using monoclonal antibodies against mouse GPIbα (p0p3, p0p4, p0p5, p0p9, and p0p11). Pretreatment with different doses of IVIG (1, 2, and 4g/kg of mouse) failed to prevent ITP in all anti-GPIbα-treated mice, except for p0p4. These results were repeated with p0p3, p0p4, and p0p5 using 2g/kg IVIG in C57BL/6 mice, and using 2g/kg of a different IVIG preparation. It has been shown that F(ab)2' fragments of the p0p antibodies can induce thrombocytopenia to the same extent as intact antibodies. To confirm that these anti-GPIbα antibodies act in an FcR-independent manner, we demonstrated that p0p3, p0p4, and p0p5 are able to induce thrombocytopenia in mice lacking activating Fc receptors (FcRγ chain −/−). Interestingly, IVIG was still able to prevent thrombocytopenia induced by p0p4 in these FcRγ chain −/− mice. We demonstrated in vitro that there are no anti-idiotype antibodies against any of the anti-GPIbα antibodies used present in IVIG. Thus, the amelioration of thrombocytopenia in p0p4-treated mice is not due to a neutralization of the antibody by IVIG. In contrast to the anti-GPIbα antibodies, anti-GPIIbIIIa monoclonal antibodies (JON1, JON2, and JON3) that induce thrombocytopenia were sensitive to IVIG treatment, which is consistent with earlier studies using other monoclonal antibodies against GPIIbIIIa. Also, JON2 was unable to induce thrombocytopenia in FcRγ chain −/− mice, confirming that this anti-GPIIbIIIa antibody is FcR-dependent. Our results suggest that ITP induced by anti-GPIbα antibodies may be mediated by FcR-independent mechanisms, many of which may be refractory to IVIG therapy. Thus, IVIG may not be as effective in treating patients with predominantly anti-GPIbα antibodies.

Intravenous Immunoglobulin G Attenuates Pulmonary Hypertension but Induces Local Neutrophil Influx in Meconium Aspiration in Piglets

Background: Pulmonary hypertension and inflammation are well-identified pathogenetic features in meconium aspiration syndrome of newborns, but current approaches to their treatment or prevention are still often unsatisfactory. Objectives: To investigate the possible protective effects of human intravenous immunoglobulin G (IVIG) on the hypertensive and inflammatory lung injury in severe neonatal meconium aspiration. Methods: Eleven newborn (10–12 days old) ventilated and catheterized piglets that received an intratracheal bolus (3 ml/kg) of a 65-mg/ml mixture of human meconium were studied for 6 h. IVIG was infused in 5 piglets 30 min before meconium administration, and 6 piglets served as controls and received the vehicle only. Results: Meconium instillation induced a biphasic pulmonary hypertensive response, which was significantly diminished by IVIG pretreatment. Similarly, IVIG improved the oxygenation of the piglets, but the intrapulmonary shunt fraction or systemic hemodynamic parameters did not differ between the study groups, except of a minor decrease in the mean arterial blood pressure caused by IVIG. The blood leukocyte count was comparable in the 2 groups. The lung tissue ultrastructural and histological changes, number of apoptotic cells and phospholipase A₂ activity were similar in the 2 groups. The amount of neutrophil accumulation, assessed by myeloperoxidase activity, was however significantly increased in macroscopically damaged lung tissue after IVIG administration. Conclusions: Our results thus indicate that IVIG treatment of newborns with severe meconium aspiration significantly diminishes the pulmonary hypertensive response and improves oxygenation, but the effects do not extend to protection of lung cellular injury.

Distinctive Efficacy of IVIG in Ameliorating Thrombocytopenia Induced by Anti-Platelet GPIIbIIIa and GPIbα Antibodies.

Idiopathic autoimmune thrombocytopenia (ITP) is an autoimmune disease characterized by autoantibody-mediated platelet destruction. The major platelet antigens that autoantibodies are directed against in ITP are GPIIbIIIa and GPIbα. Intravenous immunoglobulin G (IVIG) is a treatment used in ITP; however, some patients are refractory to this treatment and the mechanisms of action of IVIG in this disease are not fully understood. We tested the hypothesis that IVIG may not be equally effective in preventing ITP caused by GPIIbIIIa versus GPIbα anti-platelet antibodies. Thrombocytopenia was induced in Balb/c mice using three monoclonal antibodies against either mouse platelet GPIIbIIIa (JON1, 2, −3) or against GPIbα (p0p 3, 4, −5). Mouse platelet counts were performed daily from day one (pre-treatment) until day five using a flow cytometric assay. The efficacy of IVIG in inhibiting monoclonal antibody-induced platelet destruction in mice was assessed by intraperitoneal injection of IVIG (2 g/kg) 24-hours before anti-platelet antibody injections (7 mg/mouse, i.v.) on day two. We found that pre-treatment with IVIG resulted in a significantly higher platelet count on day three in all groups of anti-GPIIbIIIa-injected animals (n=3/antibody; for JON1, P=0.002; JON2, P=0.015; JON3, P=0.002) as compared to albumin-treated controls. In contrast, IVIG failed to prevent platelet clearance and thrombocytopenia on day three in two anti-GPIbα antibody-treated groups (p0p3 and p0p5, n=3/antibody), but did inhibit platelet destruction in mice that were injected with p0p4 antibody (P=0.0003). Our results indicate that the efficacy of IVIG treatment in preventing ITP induced by these anti-platelet antibodies is affected by their antigen specificities. These data also suggest that patients with ITP mediated by GPIbα may be less responsive to IVIG treatment than those with ITP mediated by GPIIbIIIa antibodies.

Expression patterns of Th1 and Th2 cytokine genes in childhood idiopathic thrombocytopenic purpura (ITP) at presentation and their modulation by intravenous immunoglobulin G (IVIg) treatment: their role in prognosis

Childhood idiopathic thrombocytopenic purpura (ITP) resolves usually after the first episode, although it may recur, and in 10% to 20% of patients develops into a chronic disorder. Evidence of the immunoregulatory role of Th1/Th2 responses in autoimmune diseases prompted us to perform a prospective study of Th1/Th2 gene expression profiles and transforming growth factor beta (TGF-beta) plasma levels in 18 children (median age, 6.4 years) with acute ITP, before and after intravenous immunoglobulin G (IVIg) infusion, and during a follow-up period (0.5-5 years). Initially, 12 of 18 patients had either low Th0/Th1 plus interleukin 10 (IL-10) or no in vivo cytokine gene expression (0). At 24 hours after IVIg infusion this pattern became 0 or Th2 (9 of 12) or remained low Th0/Th1 (3 of 12). During follow-up these patients did not relapse and maintained 0 or Th2 pattern without IL-10. Of the remaining 6 patients, 4 presented with a Th1 or Th0/Th1 pattern plus IL-10 that persisted after IVIg treatment (although interferon gamma [IFN-gamma] expression diminished) and stabilized to Th1 plus IL-10 at follow-up, which was marked by infrequent episodes of ITP. Two patients presenting with a strict Th1 pattern characterized by high expression of IFN-gamma, which remained unchanged after IVIg and at follow-up, can be characterized as chronic ITP. TGF-beta plasma levels were low in patients with active disease and increased in remission. Overall, acute ITP presents with Th1, Th0/Th1, or 0 in vivo cytokine gene expression. Stable remission is associated with a 0 or Th2 pattern. A 0 or Th2 pattern after IVIg gave the best prognosis, whereas sustained high expression of IFN-gamma and refractoriness to IVIg were the main indicators of poor prognosis.

Intravenous Immunoglobulin Inhibits Natural Killer Cell Activity In Vivo in Women With Recurrent Spontaneous Abortion

We previously reported elevation of natural killer (NK) cells in women with recurrent spontaneous abortion (RSA) of immune etiology. In this study, we investigated the effect of intravenous immunoglobulin G (IVIg) on peripheral blood NK activity in vivo in women with RSA. Blood was drawn prior to and 7-11 days after IVIg therapy in eight women with RSA. NK activity was measured using K562 as target cells for 51Cr-release assays. Serum IgG concentrations were also measured. All received 400 mg/kg/day of IVIg for 3 consecutive days. 1) Seven of eight women became pregnant. Five delivered a live born infant. Three out of five women (60%) who delivered a live born infant showed a significant inhibition of NK cytotoxicity post IVIg and the rest did not show any changes; 2) NK cytotoxicity was significantly increased in a woman who miscarried again; 3) A woman who miscarried a chromosomally abnormal fetus showed a significant inhibition of NK cytotoxicity after IVIg; and 4) Serum IgG concentration increased significantly from 9.3 +/- 3.0 mg/ml to 23.5 +/- 5.1 mg/ml post IVIg therapy. IVIg effectively inhibits peripheral blood NK activity in vivo. These results are consistent with our previous finding showing that IVIg inhibits NK cell activity in vitro. Women with RSA and elevated NK cells may benefit from IVIg treatment.

Effects of prophylactic intravenous immunoglobulin-G therapy on humoral and cellular immune components and their functions in burned patients

In this study on patients with thermal trauma, we examined the effects of standard therapy plus prophylactic polyclonal immunoglobulin G (IgG) treatment of humoral and cellular contents, cell phenotype and function of the immune system, and compare these with those found in patients receiving only standard therapy. The quantitative, peripheralblood mononuclear cell panel shows a decrease in the total number of T-lymphocytes and an increase in the natural killer (NK) cells of standard therapy patients 3 weeks following the burn. We found that intravenous IgG treatment does not have an important effect on T lymphocytes and the proportion of their subpopulations, but rather causes a significant decrease in the number of B lymphocytes and an increase in the number of NK cells. When comparing the DNA synthetic response to mitogenic and antigenic stimuli in patient's T and B lymphocytes using phytohaemagglutinin, pokeweed mitogen or allogenic mixed cells in separate in vitro cell cultures, the highest suppressive effect of thermal trauma is seen in the cells derived from the patients who had been given prophylactic IgG therapy. The presented data confirm that thermal trauma causes an immunosuppressive effect and indicate that prophylactic polyclonal IgG therapy increased the quantitative and functional suppression of the specific immune system while additionally increasing the cellular levels of the non-specific immune system, each system having been previously stimulated by thermal trauma.